Oral Histories

Marshall Rosenbluth was an American physicist who worked in the theoretical division at Los Alamos from 1950 to 1956. In this interview, Rosenbluth addresses the theoretical issues involved in designing both the atomic and hydrogen bombs. He discusses how the pressure to create a nuclear bomb before the Soviet Union affected work in the laboratory, especially in performing and checking calculations. Rosenbluth also recounts his experiences during the nuclear weapons tests at Los Alamos and Bikini Atoll. He recalls the roles of top scientists, like Edward Teller, Hans Bethe, Enrico Fermi, and Carson Mark, in the building of the hydrogen bomb. He also explains how funding and other external factors affected the hydrogen bomb’s design.

George Cowan was a physical chemist who joined the Manhattan Project in 1942. In this interview, Cowan discusses the Soviet atomic program and their effort to build a nuclear bomb. In 1949, he helped convince U.S. government officials that the radiochemistry of air samples taken from the atmosphere proved that the Soviets had detonated their own atomic bomb, rather than what many assumed was just a peaceful nuclear reactor problem. Cowan also discusses Operation Crossroads, where he helped take air samples during atomic tests at Eniwetok Atoll in 1946.

Fay Cunningham joined the Manhattan Project in 1944 as a metallurgical engineer at the Massachusetts Institute of Technology. Cunningham and his team of engineers helped to develop a mechanized process for producing crucibles that were used in the reduction of uranium and plutonium. After the war, Cunningham served as a radiation monitor for the nuclear tests at Bikini Atoll during Operation Crossroads. His job was to survey the radiological damage on navy ships that were positioned around the epicenter of the nuclear explosion. Cunningham recalls climbing cargo nets dangling from the bow of a ship while trying to hold on to a fifteen-pound Geiger counter. After Operation Crossroads, Cunningham returned to Michigan State and completed his degree in chemical engineering.

Chemist Orville Hill joined the Met Lab at the University of Chicago in May of 1942, three months after it was created. After a stint at Oak Ridge, he went to Hanford in 1944. At Hanford, he worked to improve the plutonium separation process. After the war, he worked at Los Alamos and was tasked with studying bomb debris from the Bikini atomic bomb tests. Eventually, he returned to Hanford looking for a better way to separate plutonium from irradiated uranium. In this interview, he recalls his first days at Chicago and remembers meeting Enrico Fermi. He describes the excitement and pressure of the Manhattan Project: “We were on the frontiers. We were doing things that I hadn’t dreamed of doing even a year before.”

George Cowan joined the Manhattan Project in 1942 at the Met Lab as a chemist for Enrico Fermi’s group, and also worked for Columbia University. Cowan describes his experience working with famous scientists, such as Chien-Shiung Wu and Eugene Wigner, and gives a detailed account of his role in Operation Crossroads, the first military test of the atomic bomb against Navy ships. Cowan shares some funny stories about his interaction with Arthur Compton at Oak Ridge and also recounts his meetings with Leo Szilard.